1,720,972 research outputs found
Agronomia
No full textIl testo si articola in quattro parti che analizzano e approfondicono l'agrosistema e i suoi componenti, i sistemi colturali, i sistemi aziendali e i sistemi agricoli. La quinta parte è dedicata alle appendici
Confronto tra cultivar di frumento duro in Sardegna nel 1992
No full textRisultati del confronto tra nuove cultivar di frumento duro in diversi campi della Sardegn
Ancient wheat species are suitable to grain-only and grain plus herbage utilisations in marginal Mediterranean environments
Full text linkThanks to their low fertilization requirements and high consumer demand, ancient wheats and old durum wheat cultivars represent an attractive option for the marginal areas of Mediterranean environments no longer cultivated due to the low grain yields attainable using modern wheat cultivars. Dual-purpose utilization may increase their value in these cropping systems, but no information is available on the suitability of ancient wheat species to this type of utilization. To fill this gap, Khorasan, einkorn, and emmer wheats, clipped at the terminal spikelet stage or left unclipped, were compared in a two-year field trial. The grains were sown in the month of October, in Sardinia (41°N, 80 m asl), Italy, on low-fertility soils and with low-medium fertilization rates. Einkorn cultivars produced the highest biomass yield (2–3 t ha−1), reflecting the longer time to the onset of the terminal spikelet stage (119–138 days). After clipping, all species recovered their ability to intercept radiation to the levels of the unclipped crops, but clipping lowered their radiation use-efficiency. Grain yield was not penalized by clipping: the increase in the harvest index compensated for the decrease in biomass. Here we show for the first time that ancient wheat species are suitable for dual-purpose utilization (herbage plus grain in the same season) rendering them valuable for marginal areas; this was because the early sowing adopted for dual-purpose utilization allowed them to take full advantage of their lateness in terms of herbage yield, and to bring flowering forward (i.e. make it earlier) so that a satisfactory grain yield was obtained, even under severe water stress. Dual-purpose utilization of ancient wheats increases the sustainability of mixed cropping systems, by making herbage available to animals in a critical period, without decreasing the grain yield attainable after grazing in the same season
Triticale cultivar mixtures: Productivity, resource use and resource use efficiency in a Mediterranean environment
No full textCultural systems based on mixtures of varieties may be more successful in resource use and resource use efficiency than those based on single varieties. Two triticale cultivars of different phenology (Bienvenu, intermediate; and Oceania, spring) grown in pure stands were compared with mixtures of the two (25:75; 50:50 and 75:25). Field experiments were carried out in Sardinia (Italy) in five experiments created by combining seasons, sowing date and sites. At the terminal spikelet of Bienvenu, the best mixtures produced 38, 89 and 82 % more biomass than Bienvenu in pure stand, depending on the experiment, due to a higher crop growth rate associated with a higher RUE (r = 0.60*). In the case of dual purpose utilization, this means that the winter herbage production of triticale at the terminal spikelet stage of an intermediate or winter cultivar is improved when mixed with a spring cultivar, at least in the Mediterranean environment explored here. Complementarity and differences between mixtures and pure stands in biomass production by anthesis were the exception rather than the rule. By the anthesis of Oceania, mixtures only produced more biomass than the Oceania pure stand on three occasions (11.8 and 11.9 t ha−1 vs. 9.3 t ha−1 and 10.7 t ha−1 vs. 8.7 t ha−1). In these cases, the superiority of the mixtures was due to a higher intercepted PAR (also reflected in greater transpiration), attributable to the pattern of LAI development. Differences in grain yield were only expressed when a cold stress during anthesis compromised the grain set of the spring cultivar. Here, mixtures played a fundamental role in increasing the stability in grain yield, suggesting that differences in the developmental rate between mixture components reduced the mixture sensitivity to specific abiotic stresses
Effects of clipping on the nitrogen economy of four Triticum species grown in a Mediterranean environment
No full textDual-purpose utilization (herbage + grain) of ancient wheats and old durum wheat cultivars provides an interesting option for mixed farming systems in Mediterranean environments. Interest towards these species is partly due to their low nitrogen (N) requirements, but little information is available about their N economy, particularly under dual-purpose utilization. In this two-year field trial carried out in Sardinia (Italy), we assessed whether the morpho-physiological differences between emmer, einkorn, durum and Khorasan wheat translated into different N economies, and whether these economies were differentially impacted by dual-purpose utilization. At both clipping and anthesis, biomass accumulation played a key role in the genotypic variability in N uptake. At clipping, einkorn cultivars had produced the greatest amount of biomass and removed the greatest amount of N (74 kg ha−1) thanks to their late terminal spikelet; whereas Cappelli, Khorasan and Padre Pio showed the greatest biomass production and N uptake at anthesis (212 kg ha−1) owing to their tallness and morphology. The large genotypic variation observed in total N uptake at anthesis levelled off at maturity, mainly because of the N losses occurring at the canopy level after anthesis in cultivars Cappelli, Khorasan and Padre Pio. On average, clipped crops showed a lower (by about 46 kg ha−1) total N uptake at maturity compared with unclipped crops, but dual-purpose utilization did not negatively affect the N uptake if the N removed by clipping was taken into account. Clipping did not negatively affect N partitioning to the grain as the N harvest index increased after clipping as a consequence of the increased harvest index
Role of nitrogen uptake and grain number on the determination of grain nitrogen content in old durum wheat cultivars
No full textOld durum wheat cultivars are attracting renewed attention due to their suitability to low input agricultural systems. Fourteen old durum wheat cultivars were analyzed in two field trials to assess the effect of grain number and N absorbed and translocated by the crops on grain protein percentage. The mean grain yield was below 3 t ha−1 and strongly associated with the number of grains m−2 (GNO) (r = 0.97 ***). Grain yield displayed a low sensitivity to severe terminal stressful conditions due to the ability of the old durum wheat cultivars to maintain high grain weights despite the high temperatures and short time available for grain filling caused by their late anthesis. The N source for the growing grains was mainly dependent on pre-anthesis N uptake, which was positively associated with the total biomass produced by anthesis. The tall cultivars generally left a greater amount of N m−2 (8–15 g m−2) in their straw compared with shorter ones (5–6 g m−2). The low and variable GNO modulated the amount of N potentially available for each grain and probably limited the possibility of delivering the large N source to the grains. The large grains played a positive role in determining both grain yield (by compensating for the low GNO) and grain protein percentage, as their high grain filling rate was associated with a high N accumulation rate, and hence with a high grain N content and protein percentage
Is the technological quality of old durum wheat cultivars superior to that of modern ones when exposed to moderately high temperatures during grain filling?
No full textThe growing interest in old durum wheat cultivars, due to enhanced consumer attention on traditional products and low-input agricultural systems, partly relies on their different quality characteristics compared to modern cultivars. Nine Italian durum wheat cultivars from different breeding periods were compared in two late-sown (January) field trials in order to subject their grain filling period to high temperatures similar to those expected in the future. Late sowing moved anthesis forward by about 10 days and increased the mean temperature during grain filling by 1.3 °C compared to that obtained when using the common sowing period of November–December. In these conditions, old cultivars were on average less productive than modern ones (2.36 vs. 3.54 tons ha-1, respectively), had a higher protein percentage (13.8% vs. 11.1%), a lower gluten index (24.3% vs. 56.3%), and a lower alveographic W (baking strength) (64 vs. 100 J 10-4). The differences were partly associated to variations in the gliadins:glutenins ratio. It depended on the genotype whether the
grain and semolina protein percentage and gluten strength compensated one another in terms of alveographic indices to give the dough a strength similar to that of the modern cultivars in the range of moderately high temperatures, which resulted from delayed sowing. Further studies aimed at exploring the genetic variability of quality traits are therefore advisable.JRC.D.5 - Food Securit
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